The present invention relates to an optical module and a method for manufacturing an optical module.
High-speed optical communication, which uses optical signals instead of electric signals, involves an optical module that converts electric signals to optical signals and optical signals to electric signals. An optical module basically includes a light emitting element and a light receiving element that are arranged on an optical transmission medium, such as an optical waveguide. The light emitting element, which may be a semiconductor laser, converts electric signals to optical signals. The light receiving element, which may be a photodiode, converts optical signals to electric signals (refer to, for example, Japanese Laid-Open Patent Publication Nos. 2011-242706 and 2009-175418).
FIG. 21 shows a referential example of optical coupling between a light emitting element and an optical waveguide. An optical waveguide 91, which is arranged on a substrate 90, includes one end surface that is inclined at 45 degrees with respect to a surface 90A of the substrate 90. A reflective mirror 92 is formed on the inclined end surface of the optical waveguide 91. Light emitted from a light emitting element 93 is reflected by the reflective mirror 92 into the optical waveguide 91.
To enable such optical coupling in the referential example, there is a need to accurately align the optical axis of the light emitting element 93, the point of reflection on the reflective mirror 92, and the position of the optical waveguide 91 at which the reflected light from the reflective mirror 92 enters the waveguide. Such alignment is achieved through, for example, active alignment. Active alignment involves measurement of the amount of light emitted from an output end of the optical waveguide 91 during movement of the reflective mirror 92 and the optical waveguide 91 (or specifically the substrate 90) when light is output from the light emitting element 93. The light emitting element 93 and the substrate 90 are then fixed at positions corresponding to the maximum amount of light emitted from the output terminal of the optical waveguide 91.
However, an information communication device or an information processor includes a large number of channels that carry optical signals. Thus, when active alignment is performed for each channel of such a device, a great amount of time is consumed.